WSET.com - ABC13Some of Us Call Them Bowling Balls by Sean Sublette

The rain. Oh, the rain.

Early last week, we all saw it coming. If you overhear meteorologists talk about cutoff lows or bowling balls, it means a wet period is ahead.

The signs were there a little bit before that, but admittedly, I did not want to believe them at first. Maybe the simulations were wrong. The pattern won't really last that long, will it?

So far it has. While this pattern has worn out its welcome, it is not that unusual for spring.

During the course of the spring, the average position of the jet stream moves from the Central United States (winter) to Central Canada (summer). Remember that the jet stream is very much like a river of fast moving air. So as that high energy motion retreats poleward, small areas of slower wind speeds effectively break off from the southern side of the jet. Depending on other conditions nearby in the upper atmosphere, those slower areas can begin to spin and stall. They are normally referred to a cutoff lows, meaning they are cutoff from the main upper level winds.

Immersed in those cutoff lows is unusually cold air in the middle and upper levels of the atmosphere. And as the stronger May sunshine warms the ground, the air in contact with the ground heats up very effectively.

As that warmed air rises into the much colder air above it, it becomes more buoyant, almost like a hot air balloon. It quickly rises until it cools enough to form clouds and rain. Sometimes, thunderstorms and hail will form as well.

So when we find ourselves under these cutoff lows in the spring, it is perfectly normal to expect at least two or three days of frequent showers and thunderstorms. But this time is a little different, as we have seen additional surges of wind energy diving into the cutoffs from the north and northwest. And that further intensifies the cutoffs and slows their progression.

One positive: This pattern has effectively removed the drought that developed from mid winter to early spring, and it puts us in a good position was we gear up for the hot summer months.